Nozzle



Aug. 17, 1965 H. C. SIMMONS ETAL NOZZLE Filed Aug. 29, 1962 FIG. I

FIG. 2

3 INVENTOR HAROLD C. SIMMONS 8 I WRENCE B. O'SICKEY 6%, 7%

ff ATTORNEYS United States Patent 3,201,050 NOZZLE Harold C. Simmons, South Euclid, and Lawrence B. OSickey, University Heights, Ohio, assignors to Parker-Hannifin Corporation, Cleveland, Ohio, a corporation of Ohio Filed Aug. 29, 1962, Ser. No. 220,338 9 Claims. (Cl. 239-453) The present invention relates generally as indicated to a nozzle and, more particularly, to a fuel injection nozzle for gas turbines and the like having combustion chambers into which liquid fuel is introduced in finely subdivided spray form. This application is a continuation in-part of our application Ser. No. 51,613, filedAugust 24, 1960, now Patent No. 3,093,317.

At the present time a popular form of nozzle for this purpose is the variable orifice nozzle having a springbi-ased pintle valve formed with a conical head adapted to cooperate with the sharp edge or seat of the discharge orifice formed in the nozzle body to provide a variable area annular passage=through which the fuelis metered and sprayed. With such nozzle, the spray cone angle is determined by the conical head of the pintle valve, the conical sheet of fuel breaking up into a spray beyond the base of the conical head. Generally, the edges of the discharge orifice and of the base of the pintle valve head must be free of burrs and other imperfections, otherwise, the quality of the spray is not as good as desired. Likewise the axes of the discharge orifice and of the conical head of the pintle valve must be truly coincident, or very nearly so, in order to obtain the proper quality ofspray necessary for efficient combustion of the fuel in the engine. The presence of burrs, imperfections, eccentricities, etc., are all the more critical in known nozzles at low fuel flows when the pintle valve has only moved a very small distance away from its position of engagement with the edge of the discharge orifice.

With theforegoing in mind, it is a principal object of this invention to provide a nozzle which produces a better quality spray throughout the entire fuel flow range thereof than is obtainable with known forms of nozzles.

, It is another object of this invention to provide an improved nozzle construction, the superior performance of which is hardly affected by the presence of slight burrs, imperfections, and eccentrieities of the discharge. orifice and pintle valve head.

It is another object of this invention to provide a nozzle in which the fuel is discharged therefrom through a variable area orifice that is composed of parallelplane annular faces of the nozzle body and pintle valve respectively, and in which the resulting plane circular sheet of fuel is converted into a spray cone of fine droplets by impingement of the fuel on the internal face of a deflector that surrounds said variable area orifice.

\ It is another object of this invention to provlde a nozzle having a conical deflector against which the. stream of fluid issuing from the nozzle impinges to break up the stream into fine droplets and to control the spray cone J finely divided particles and for accurate control of the spray cone angle Other objects andadvantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed draw- 3,201,050 fiat-exited Aug. 17, 1965 ings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. 1 is a central longitudinal cross-section view through one form of nozzle embodying the present invention;

FIG. 2 is a cross-section view taken substantially along the line 2-2, FIG. 1; and

FIG. 3 is a much enlarged fragmentary crosssection view showing how the stream of fuel emerges radially from between the seats of the pintle valve and the nozzle body and impinges against the internal tappered walls of the surrounding deflector to produce the desired spray cone.

Referring now more particularly to the drawings, and first to FIG. 1, the nozzle 1 there shown comprises a nozzle body 2 having an orifice bushing 3 mounted therein at its forward end, said bushing 3 being fashioned as a guide 4 for the pintle valve 5.

The pintle valve 5 has a knurled or serrated cylindrical head 6 on which is secured as by brazing a tungsten carbide or equivalent bushing 7. Adjacent said pintle valve head 6 there is provided a neck portion 8 that defines with the orifice bushing 3 an annular passage 9. j The juxtaposed ends of bushings 3 and 7 are formed with plane annular seats 10 and 11, which may be of equal outside and inside diameters.

The rear end of the pintle valve 5 has axially adjustably mounted thereon a spring follower 12 for the spring 14 which is adjustably compressed between said follower 12 and the nozzle body 2 as by providing C-shaped shims 15 of different thicknesses on the groove 16 of the stem 17 of the pintle valve 5, a cup-shaped retainer 18 being employed with cotter pin 19 for holding the selected shim 15 in place for predeterminedly compressing spn'ng14. Preferably, the spring 14 is fabricated from a'length of round tubular stock which has one or more helical slots 20 through the wall thereof terminating short of the ends and arranged to eliminate tendency of canting of the ends with respect to each other and with respect to the pintle valve axis.

It can be seen that when the fuel pressure acting on the area A of the pintle valve 5 exceeds the preload of spring charge of fuel radially outward between said seats. As

desired spray cone angle. The axial position of the intersection of these cones 23 and 24 relative to seats 10 and 11 the fuel pressure increases the gap between seats 10 and 11 will progressively increase to permit increased flow of fuel from the nozzle.

It is to be noted that the orifice and pintle valve bushings 3 and 7 are coaxial and preferably of the same inside and outside diameters, that the orifice bushing 3 projects axially beyond the surrounding deflector 21 of the nozzle 1, and that the pintle valve bushing projects rearwardly of the head 6 As aforesaid, there is provided around the orifice and pintle valve bushings 3 and 7 a deflector 21 which,

as shown in FIG. 1, is shaped internally to provide a double-angled conical surface 23-24 of which both angles are preferably, but not necessarily, of apex angle greater than but substantially less than For good results, the interior conical surface 23-24 of the deflector 21 comprises adjacent coaxial cones 23-24 of different apex angles, with the larger apex angle of cone 23 being about 5 to 15 (preferably 10) greater than the desired spray cone angle, and with the smaller apex angle of 24 being about 5 to 15 (preferably 10) less than the is not critical but it is preferred that the line 25 be in the same plane as the pintle valve seat 11 when the pintle valve is the fully open position of FIG. 3 as determined by the maximum fuel pressure available. The deflector 21 is herein shown as being welded at several points to the nozzle body 2.

With a nozzle structure as hereinabove-described, and as best shown in FIG. 3, slight eccentricity of the pintle valve seat 11 with respect to the discharge orifice seat 16 is of no moment in respect of overall improved nozzle performance nor are slight burrs or other imperfections in these seats or the edges thereof. When the nozzle 1 is in operation with the pintle valve 5 unseatedas in FIG. 3, the fuel will flow radially outwardly through the circular gap between the plane annular seats and 11, and will impinge, as shown, on the doubleangled conical internal face 23-24 of the surrounding deflector 21 to break up the fuel into the fine droplets having the desired spray cone angle which, as aforesaid, is in between the apex angles of the cones 23 and 24.

Within the pintle valve biasing spring 14 is the damping and stop sleeve 26 which, together with the sliding fit of follower 12 in bore 27, is effective to dampen vibrations or flutter of the pintle valve 5. Accordingly, turbulent flow of fuel between the seats 10 and 11 and fuel pressure pulsation and fluctuation will not cause fluttering or vibration of the pintle valve 5, the'hydraulic dashpot 28 defined by the damping sleeve 26 and follower 12 being effective to prevent such movements of the pintle valve. Moreover, the seats 10 and 11 are thereby prevented from pounding against each other. Leakage of fuel between spring 14 and stop sleeve 26 bleeds stagnant fuel from dashpot 28 and, in addition, engagement of sleeve 26 with shoulder 29 prevents overstressing of the spring 14.

By way of illustration, it has been found that a nozzle according to the present invention having. a rating of 1000 lbs/hr. fuel flow at 800 p.s.i. fuel pressure and an opening pressure of 100 p.s.i. as set by the pintle valve spring 14 provides good spray quality even at low fuel flows of 30 lbs/hr. In contradistinction, variable area nozzles of the same rating but employing conical head pintle valves have much deteriorated spray quality at fuel flows from 50 lbs./ hr. and less.

In the case of the nozzle shown in FIGS. 1 and 2, for example, wherein the discharge orifice in bushing 3 is of .088 diameter and the stem 8 of the pintle valve 5 is of .038" diameter, good results as aforesaid have been obtained by making the seats 10 and 11 of approximately .020" radial width. The conical surfaces 23 and 24 of about 128 and 102 apex angle respectively then should intersect as represented by the line which is of about .11" diameter and which is substantially in the same plane as the seat 11 of the pintle valve 5 when the latter is in open position (about .012" gap between seats 10 and 11) under the influence of the maximum available fuel pressure.

Finally, with reference to FIG. 3, it will be seen that when the pintle valve 5 is unseated as shown, the fuel will flow radially as a relatively thin sheet between the plane annular seats 10 and 11, and it is believed that by reason of the provision of the relatively sharp inner edges and 31 there will be a vena contracta 32 where the fuel first enters the orifice defined between the plane annular seats 10 and 11. The outer face 34 of the fuel sheet, in the rated flow positionof the pintle valve 5, will coincide with the intersection 25 of the faces 23 and 24. The inner face 35 of the fuel sheet will impinge on surface 23 as shown and will be reflected thereby and will intersect like elements between faces 34 and 35.

V The resultants 36,"in turn, will impinge on face 24 and in the combustion chamber.

A minor portion of the fuel is sprayed as denoted by the line 38, the spray cone angle being measured by line 38 and the deflector cones 23-24 being related as aforesaid to this measured spray cone.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employcd.

We therefore particularly point out and distinctly claim as our invention:

1. A fuel injection nozzle comprising a body having an inlet for fuel under pressure and a discharge orifice, said orifice terminating in a plane annular seat with relatively sharp inner and outer edges; a spring biased fuel pressure actuated pintle valve movable in said body and having a plane annular seat also with relatively sharp inner and outer edges, said pintle valve being movable under the influence of progressively increasing fuel pressure in said inlet from a position whereat said seats are in mating engagement to a position whereat said seats are axially spaced apart a progressively increasing distance for discharge of fuel from between said seats; and a deflector on said body disposed around said seats and against which the fuel emerging from between said seats impinges and thus is broken up into spray form; said deflector having a first frusto-conical internal surface radially outward of said seats when thus spaced apart whose apex angle is greater than that of the desired spray cone of the fuel, and a second adjacent frusto-conical internal surface axially beyond said seats when thus spaced apart whose apex angle is less than that of the desired spray cone of the fuel.

2. The nozzle of claim 1 wherein said apex angles are respectively 5-15 greater than and less than that of the desired spray cone of the fuel.

3. The nozzle of claim 1 wherein said apex angles are respectively about 10 greater than and less than that of the desired spray cone of the fuel.

4. A fuel injection nozzle comprising a body having an inlet for fuel under pressure and a discharge orifice, said orifice terminating in a plane annular seat; a springbiased fuel pressure actuated pintle valve movable in said body and having a plane annular seat, said pintle valve 7 being movable under the influence of progressively increasing fuel pressure in said inlet from a position whereat said seats are in engagement to a position whereat said seats are spaced apart a progressively increasing distance for discharge of fuel from between said seats; spring means between said body and pintle valve biasing the latter as aforesaid; a spring follower on said pintle valve defining with said body a fluid damping chamber to reduce vibration and flutter of said pintle valve; and a deflector on said body disposed around said seats and against which the fuel emerging from between said seat impinges and thus is broken up into spray form.

5. A nozzle according to claim 4 whereinsaid spring means has a sleeve in telescoped relation therewith to permit leakage from such damping chamber. 3

6. A nozzle according to claim 4 wherein said spring means has a sleeve in telescoped relation therewith; and wherein said spring follower has a plunger portion movable in a bore ofsaid body; said sleeve and plunger portion permitting leakage of fluid into and from such damping chamber.

V 7. A fuel injection nozzle comprising a body-havingan I inlet for fuel under pressure and a discharge-orifice, a

pintle valve movable in said body, spring means between said body and valve; and a spring followerand a spring guide defining with said body a fluid damping chamber to reduce vibration and flutter of said valve. 7 a

8. A nozzle according to claim 7 wherein said follower and guide permit leakage of fluid into and from such' damping chamber.

9. A nozzle according to claim 7 wherein said spring 1 5 6 guide comprises a sleeve between said body and follower 3,042,317 7/62 Simmons 239453 which constitutes a stop to prevent overstressing of said' 3,093,317 6/63 Simmons et a1. 239453 Spnng means- FOREIGN PATENTS References Cited by the Examiner 5 628,922 7/27 Rama UNITED STATES PATENTS 1,169,811 9/58 France. 1,893,457 1/33 Tartrais 239-453 248,119 3/11 Germany: 2,096,814 10/37 Laessker 239-453 499,040 1/39 Great B 2,145,429 1/39 Nelson 239-533 2 55 119 41 Kennedy 239453 10 W- KIRBY, Prlmar) Exammer- 2,990,123 6/61 Hyde 239-453 LOUIS J. DEMBO, Examiner. 

7. A FUEL INJECTION NOZZLE COMPRISING A BODY HAVING AN INLET FOR FUEL UNDER PRESSURE AND A DISCHARGE ORIFICE, A PINTLE VALVE MOVABLE IN SAID BODY, SPRING MEANS BETWEEN SAID BODY AND VALVE; AND A SPRING FOLLOWER AND A SPRING GUIDE DEFINING WITH SAID BODY A FLUID DAMPING CHAMBER TO REDUCE VIBRATION AND FLUTTER OF SAID VALVE. 